• Notes: The Hole in the Notes: The Hole in the Ozone LayerOzone Layer• If you were gone, use the notes If you were gone, use the notes

handout and this presentation to get handout and this presentation to get caught up.caught up.

Troposphere

Stratosphere

Mesosphere

Thermosphere

• 1. What are the components of solar 1. What are the components of solar radiation (sunlight)radiation (sunlight)

• 9% UV9% UV• 46 % light46 % light• 45 % infrared: a.k.a. 45 % infrared: a.k.a. ““heat wavesheat waves””

EM spectrum

Electromagnetic SpectrumElectromagnetic Spectrum

2. The Hole in the Ozone layer2. The Hole in the Ozone layer• Area over Antarctica where ozone (OArea over Antarctica where ozone (O33) loss ) loss

exceeds 50 % exceeds 50 % • Happens every Sept., Oct. Nov. since 1980sHappens every Sept., Oct. Nov. since 1980s• It cannot be seenIt cannot be seen

Ozone Hole Animation

Jan. Feb. March April May June

July Aug. Sept. Oct. Nov. Dec.

Next: Watch 15 minutes of video “The Hole Story”

troposphere

stratosphere

mesosphere

Troposphere

Stratosphere

Mesosphere

Thermosphere

33. Ingredients for O. Ingredients for O33 destruction destruction

• A. Polar Vortex:A. Polar Vortex: isolates the air over isolates the air over Antarctica Antarctica ((polar vortex))

• B. B. Clouds of ice crystals in stratosphere over in stratosphere over S. PoleS. Pole

• C. C. SunlightSunlight: Breaks apart the CFC molecules.: Breaks apart the CFC molecules.• D. D. CFCsCFCs: provide the chlorine (: provide the chlorine (““bad guybad guy””))

• CFC use began to increase rapidly in the 1960sCFC use began to increase rapidly in the 1960s

. . . continued from yesterday.. . . continued from yesterday.

4. Some uses of CFCs?4. Some uses of CFCs?

• Refrigerators, freezers: 15 % (FREON)Refrigerators, freezers: 15 % (FREON)• Air conditioners in cars and homes: 20 %Air conditioners in cars and homes: 20 %• Aerosols: 15 %Aerosols: 15 %• Foams: 24 %Foams: 24 %

• the current hole in the ozone layer

The destructive chemistry:The destructive chemistry:

• CClCCl2 2 FF22 + light ---> Cl + CClF+ light ---> Cl + CClF22

• Cl + OCl + O3 3 ---> ClO + O---> ClO + O22

• ClO + O ---> Cl + OClO + O ---> Cl + O22

Rowland and MolinaRowland and Molina1974 paper1974 paperNobel Prize 1995Nobel Prize 1995

NextRowland and Molina

5.5.• Polar vortex?Polar vortex?

• June - Nov.June - Nov.

• Ice crystals?Ice crystals?

• Sunlight?Sunlight?• Sept. - JuneSept. - June

• CFCs?CFCs?

• Isolates the air over Isolates the air over AntarcticaAntarctica

• Provide a surface for one Provide a surface for one of the reactionsof the reactions

• Breaks CFC apartBreaks CFC apart

• Provide Chlorine atom Provide Chlorine atom (bad guy)(bad guy)

What it doesWhat it does

NEXTNEXTThe whipped topping demonstrationThe whipped topping demonstration

6. Risks to humans

• SunburnSunburn• Skin cancer: 9,500 deaths per year in Skin cancer: 9,500 deaths per year in

USA (How does it kill?)USA (How does it kill?)• Decreased immune systemDecreased immune system• CataractsCataracts

Caused by UV exposure

Melanoma: Benign? Malignant (5%)?

What about tanning beds?

170,000 in Tanzania

In some Tanzania albino people are killed andtheir body parts are used by witch doctors to make potions - believe skin, bones, blood of albinosbring wealth and luck.

7. Precautions7. Precautions

• Avoid the midday sun (noon-3p.m.)Avoid the midday sun (noon-3p.m.)• No tanning beds! No tanning beds! • Sunscreen, lip balm (at least SPF* 15)Sunscreen, lip balm (at least SPF* 15)

• Hat, long sleevesHat, long sleeves• Sunglasses (UV filtering)Sunglasses (UV filtering)

Slip, Slop, Slap!Slip, Slop, Slap!

8. Why is exposure more of a concern in 8. Why is exposure more of a concern in places like Denver, Butte and Helena?places like Denver, Butte and Helena?

• Altitude • (a.k.a. elevation)

Which Helena High sport is most likely to contribute to development of cataracts later in life?

NextRowland and Molina

Montreal Protocol called most successful treaty in UN History